Two methods of horizontal gene transfer.

Pseudomonas has a plasmid containing the mer operon, which includes a gene for mercuric reductase. The enzyme catalyzes the reduction of the mercuric ion Hg2+ to the uncharged form of mercury, Hg0 Hg2+ is quite toxic to cells, Hg0 is not.

1. What condition would induce this operon to be transcribed and the transcript to be translated into the proteins including mercuric reductase?

2. The protein encoded by the mer operon binds to Hg2+ outside the cell and brings it into to the cell, why would a cell bring in a toxin?

Two daughter cells are most likely to inherit which one of the following from a parent cell?

3. a change in a nucleotide in mRNA, tRNA or rRNA?

4. Which of the following is NOT a method of horizontal gene transfer? Contrast two methods of horizontal gene transfer.

conjugation, integration of a transposon, transduction or transformtion

5. Amino acid sequences for the viral coat of HIV were sequenced from three HIV patients. Of the amino acid sequences shown which are most closely related?

Patient A Asn Gln Thr Ala Ala Ser Lys Asn Ile Asp Ala Leu

Patient B Asn Leu His Ser Asp Lys Ile Asn Ile Ile Leu Leu

Patient C Asn Gln Thr Ala Asp Ser Ile Val Ile Asp Ala Leu